As an abnormality detection system of a mobile robot such as a legged mobile robot, there is known the technology taught by Japanese Laid-open Patent Application No. 2001-150374. This system diagnoses itself for abnormalities and informs the user (operator) of the result of the diagnosis by voice via an audio output device and a communications interface, in a natural conversational manner.
However, in the aforesaid prior art, only the diagnosis result is outputted and no measure whatsoever is taken with regard to the point of driving the robot 1 into a stable state when an abnormality occurs.